You get a call from a customer who reinstalled Windows on his computer after a crash. Fortunately, he had recently backed up all this data to an external USB drive and was able to restore everything on his NTFS-formatted file system. However, he had a number of encrypted files that he had backed up along with the rest of his data that he can no longer access. What happened? A. NTFS-encrypted files cannot be backed up, and when the computer crashed, those files were lost forever. When the customer tried to restore these files, only corrupted versions were restored. B. NTFS-encrypted files are not restored with the original encryption key used before the backup process and thus become inaccessible. C. When the customer reinstalled Windows, even though he used his old username, the computer assigned him a completely different security identifier (SID). The restored NTFS-encrypted files are looking for his original SID. D. When the customer reinstalled Windows, he didn’t use his original username. The restored NTFS-encrypted files are looking for the original username. Solution C. NTFS encryption used the customer’s SID to associate with the encrypted file. Now that the customer reinstalled Windows, a completely new SID was assigned to the customer. Without the original SID, he can’t access the encrypted files. A third-party decryption application may help him access his encrypted data. .